1. Field of the Invention
This disclosure relates to a liquid crystal display (LCD) device, and more particularly to an LCD device of an in-plane switching (IPS) mode.
2. Discussion of the Related Art
Recently, LCD devices of an IPS mode have been developed which improve a viewing angle of the image. The IPS mode LCD device controls the directional alignment of liquid crystal molecules by the induction of an in-plane (or a horizontal) electric field between two electrodes formed on one substrate. Such an IPS mode LCD device will now be described referring to the attached drawings.
FIG. 1 is a planar view showing an IPS mode LCD device according to the related art. As shown in FIG. 1, an IPS mode LCD device includes gate lines 12 and data lines 15 crossing each other perpendicularly and defining pixels on a substrate, thin film transistors formed at each intersection of the gate and data lines 12 and 15, as well as common electrodes 24 and pixel electrodes 17 alternating with each other in a parallel line within each pixel and inducing a horizontal electric field. The common electrodes 24 are formed in a united body along with a common line 25 which is parallel to the gate lines 12. The common electrodes 24 receive a voltage from outside the active area.
The IPS mode LCD device of such a configuration applies voltages to the common electrode 25 and the pixel electrode 17, both of which are formed on a same substrate, thereby inducing an in-plane electric field on the substrate in a horizontal direction. The in-plane electric field rotates liquid crystal molecules, causing them to maintain a horizontal state with respect to the substrate.
However, as the pixel electrode 24 and the common electrode 17 are arranged parallel to the data lines 15 (or along the direction of the data lines 15), the area of the pixel region occupied by the pixel and common electrode 24 and 17 is enlarged. Therefore, the aperture ratio of the IPS mode LCD device deteriorates.